They believe much of the ivory their teams found will have come from animals slaughtered by gangs in central Africa.

Any international ivory trade must be sanctioned by Cites, the United Nations Convention on International Trade in Endangered Species.

Sidestepping the law

Domestic trade within a country is a matter of national legislation. Ivory Coast banned the trade in 1997, and it is supposed to be controlled by law in Senegal and Nigeria.

But a report by Traffic and WWF says investigators found more than 4,000 kilogrammes of "illegal" ivory on public display in nine cities in the three countries.

A placid life for some

It says this volume of ivory represents the tusks of more than 760 elephants, although recent data from IUCN-The World Conservation Union suggest there may be no more than 543 elephants left in the three countries.

The report is entitled More Ivory Than Elephants: Domestic Ivory Markets In Three West African Countries.

One of its authors, Tom Milliken, of Traffic, said: "These studies show just a snapshot of the problem.

"When we factor in all of the uncontrolled manufacturing, buying and selling over a year, these numbers climb to frightening dimensions."

The report says much of the ivory found on sale came from the Democratic Republic of Congo, Cameroon, the Central African Republic and Gabon.

It says these countries make up Africa's most troubled region for elephant conservation.

Kept in the dark

The authors say inadequate legislation and poor law enforcement allow the trade to flourish in the three countries surveyed, and that this threatens elephants' survival both there and in central Africa.

They say: "All three governments are in breach of ivory market control requirements... under Cites. Furthermore, the wildlife authorities responsible for implementing Cites are systematically barred from the ports of entry and exit."

Dr Susan Lieberman of WWF said: "Not only is there a lack of political will to implement Cites, allowing traders to act with immunity from prosecution, but corruption is preventing effective controls on the ivory trade.

Two that got away

"It is time that Nigeria, Ivory Coast and Senegal took concrete steps to effectively implement Cites in their countries."

The report says the situation is most alarming in Nigeria, with higher volumes of ivory identified than in a previous undercover survey carried out in 1999.

It says: "If Nigeria fails to comply with Cites requirements to regulate internal trade in ivory by March 2004, it could find that all legal trade in Cites-listed wildlife species to and from the country is suspended."

But the report makes it clear that not all the responsibility for the trade belongs to the three countries themselves.

It says the main buyers of the ivory are expatriates, tourists, and business visitors from France and Italy, China and South Korea, and the US. In some cases diplomats are involved.